This investigation is designed to extend the experimental model previously designed to quantitate the biologic and physical aspects of bone transplant repair. Utilizing the model, studies will be conducted to ascertain the effect of artificial apertures on the rate and amount of repair in isogeneic cortical canine semental bone transplants. It is anticipated from previous pilot studies that the apertures will not significantly weaken the transplant and may significantly accelerate the reparative process. The rates, extent and spatial configuration of repair will be quantitated by continuous tetracycline labeling, microradiography, radiography, torsional loading to failure, and computed maximal stress analysis. Additional studies will be carried out to quantitate the strength of the union between the transplant and host. This data will provide a guide as to the time of stress upon transplants that induces "delayed" failure. Finally data on comparable human transplants will be generated.